Colton Hansen
Brigham Young University
Dr. William McCleary Ph.D. Associate Professor Bill_mccleary@byu.edu Antibiotic resistance is a new issue faced by the medical field, and as a result there has been a push for research into alternative forms for treatment of bacterial infection. The focus of our efforts in Dr. William McCleary's research lab have been centered around the characterization of E. coli specific bacteriophages. The hope is to better understand the bacteriophage host interaction with the long term goal of investigating the use of bacteriophages to treat antibiotic resistant bacterial infections. The cellular infections of These bacteriophages have been shown to only target the FhuA protein which is an outer membrane iron siderophore transporter. This transports ferrichrome specifically. The three bacteriophages that have been the focus of our studies are named phage 37, phage 41, and phage 60. Many tests have been performed to characterize these novel bacteriophages. These include the sequencing of the individual phage genomes, electron microscopy, and the identification of which protein loop is bound by each phage. The focus of my work has been centered around identifying the lysogenic potential of P37, P41, or P60. During our research we have seen that E. coli quickly mutates to develop resistance to these phage when grown in favorable conditions. E. coli becomes resistant to all of these phage as soon as the FhuA gene is knocked out or mutated. In order to test if these phage could become lysogenic, the E. coli strain, MG1655, was grown on fully nutritious LB agar plates for 3 to 5 days at a time, spotted with 5uL of phage. This promoted the formation of bacterial mesas which are healthy phage resistant colonies inside of a clearing caused by the phage. Subsequent verification of phage resistance led us to perform polymerase chain reaction tests that would hopefully show us that the phage DNA had been integrated into the host genome. These tests have been done under normal rich media and also under nutrient poor/growth limiting media. Despite the presence of genes that code for recombinase proteins, none of the tests that have been run have indicated a tendency for these bacteriophages to become lysogenic. The tests run to confirm this have not ever shown an example of a lysogenic strain of E. coil with these three bacteriophage. Being able to show that it does not happen or at least it is very unlikely for a certain phage to become lysogenic means that it can be trusted as a good ingredient for any antibiotic-resistant phage treatments. The conclusion of this part of the experiment is that Phages 37,41, and 60 are non-lysogenic and do not achieve phage resistance through super infection exclusion.